Poly(amic acid) solution and polyimide film or polymide-coated material obtained therefrom

Abstract

This invention provides a poly(amic acid) solution which does not contain aprotic polar solvents such as DMF, NMP, DMAc, DMSO, as well as a polyimide film obtained therefrom having appropriate flexibility and a small coefficient of linear thermal expansion and a coated material in which the polyimide film is formed on a substrate. More particularly, it provides a poly(amic acid) solution which has an aromatic poly(amic acid) and a tertiary amine as the solute and a water soluble alcohol compound and/or a water soluble ether compound as the solvent and contains substantially no aprotic polar solvent, as well as a polyimide film obtained from the poly(amic acid) solution and a coated material obtained by forming the film on a substrate.

What is claimed is: 
     
       1. A poly(amic acid) solution which comprises an aromatic poly(amic acid), a tertiary amine as a solute and a water soluble alcohol and/or a water soluble ether as a solvent, wherein said solution contains substantially no aprotic polar solvent, wherein said tertiary amine is selected from the group consisting of N,N-dimethylhexylamine (C6N), N,N-dimethyloctylamine (C8N), N-N-dimethyldecylamine (C10N), N,N-dimethyldodecylamine (C12N), N,N-dimethyltetradecylamine (C14N), N,N-dimethylhexadecylamine (C16N), N,N-dimethyloctadecylamine (C18N) and N,N-dibutyl-2-ethylhexylamine. 
     
     
       2. The poly(amic acid) solution according to claim 1, wherein said polyamic acid comprises a dianhydride component and a diamine component, and the dianhydride component of said aromatic poly(amic acid) comprises pyromellitic dianhydride and/or benzophenonetetracarboxylic dianhydride and the diamine component comprises diaminodiphenyl ether and/or paraphenylenediamine. 
     
     
       3. The poly(amic acid) solution according to claim 1, wherein said polyamic acid comprises a dianhydride component and a diamine component, and the dianhydride component of said aromatic poly(amic acid) is pyromellitic dianhydride and the diamine component comprises 50 to 83 mol % of diaminodiphenyl ether and 17 to 50 mol % of paraphenylenediamine. 
     
     
       4. The poly(amic acid) solution according to claim 1, wherein said water soluble alcohol is methanol. 
     
     
       5. The poly(amic acid) solution according to claim 1, wherein said water soluble ether is tetrahydrofuran.